1. Field of the Invention
The present invention is directed to an easily assembled, leakproof liquid dispensing pump for dispensing liquid from a container, more particularly a container of the type used for packaging household products in convenient form for intermittent consumer use. Typical applications of the pump here concerned include use on portable containers for packaging liquid consumer products as diverse as household cleaners, polishes, lubricants, pesticides, room deodorizers, perfmes and other personal products such as antiperspirants and deodorants. These containers are generally adapted to be hand-held and the pump to be operated by one of the fingers of the user on that same hand. The containers have a wide variety of shapes and sizes, and may be fabricated from glass, plastic, metal, or any other material not adversely affected by the particular liquid desired to be stored.
Frequently the containers and liquid dispensing pumps, where used to package and dispense inexpensive liquid consumer products, are intended to be disposable after the container's contents have been used. Therefore, the dispensing pumps employed for such applications must be mechanically simple, having components which are inexpensive to manufacture and easy to assemble in order to make the package economically feasible.
Large numbers of these containers are commonly filled with liquid consumer products and capped with the dispensing pumps at a central loading or filling facility which then ships them to the usual retail distributing centers and consumer sales outlets. Often during shipment and stockroom handling, as well as during home use, the containers may be dropped or accidentally inverted. Therefore it is important that each dispensing pump have provision for preventing leakage from its associated container, regardless of the container attitude. A further consideration in pumps of this type is that they should be effective to dispense all of the liquid contents from the container, and this requires proper venting to permit complete evacuation of the contents. Such venting arrangement, however, must not give rise to leakage problems.
2. Description of the Prior Art
Many forms of pumps for dispensing liquids from a household container are presently known; for example, liquid pumps of this general type are disclosed in U.S. Pat. Nos. 2,547,109; 2.889,964; 2,956,509; 3,062;416; 3,228,347; 3,228,570; 3,229,864; 3,248,021; 3,331,559; 3,362,344; 3,399,836; 3,583,605; 3,744,849; 3,797,748; and 3,799,448.
In spite of such extensive work in the art, many of the pumps disclosed in the patents set forth above still have one or more drawbacks. Some, for example, are mechanically complicated and therefore expensive to manufacture and uneconomical for use in throw-away packaging. Other designs do not provide efffective sealing of the means employed for venting the interior of the container, as needed to obtain complete discharge of the contents; while othes do not provide efficient means for adequately venting air into the container to insure rapid emptying of the contents if so desired.
It is the purpose of the present invention to provide an improved dispensing pump of the type described which overcomes some of these drawbacks.